Evidence collection25 September 2020

Spotlight on vector-borne disease

Evidence-based veterinary medicineSmall animalsMedicine

Introduction

The recent report of the first human case of UK-acquired babesiosis, along with a probable case of tick-borne encephalitis, highlights the importance of being aware of vector-borne diseases

Vector-borne diseases are infections caused by parasites, bacteria and viruses, which are transmitted by an arthropod vector, such as ticks, mosquitoes, and sand flies. In domestic pets these are most commonly diagnosed in animals that have travelled abroad or been imported.

An article summarised in our journal watch reported on the prevalence of a number of vector-borne diseases, based on owner reports of testing following importation to the UK. While this may not be the most accurate way of assessing infection (for example it is reasonable to assume that the positive tests for rabies are more likely to have been blood tests to assess response to vaccination) they do give an indication of the prevalence of these diseases in imported dogs.

Further evidence of the risk of vector-borne disease in imported dogs is provided by a study of dogs from a single kennel in South-Central Romania, which rehomes dogs both within Romania and abroad.

As these diseases are seen infrequently in practice in the UK, it can sometimes be challenging to access the relevant information regarding diagnosis and treatment. This Spotlight brings together a range of papers, and other evidence-based resources, that provide a useful reference for up to date knowledge on these diseases.

References

Norman, C., Stavisky, J., and Westgarth, C. (2020) Importing rescue dogs into the UK: reasons, methods and welfare considerations. Veterinary Record, 186, p. 248. https://doi.org/10.1136/vr.105380
UK Government (2020) Rare tick-borne infections diagnosed in England [online] Available at: https://www.gov.uk/government/news/rare-tick-borne-infections-diagnosed-in-england [accessed 7 September 2020]

Guidelines

Guidelines can provide a succinct summary of evidence on a particular topic. However, there is no standard format for guidelines, some may have clearly defined questions, a structured strategy to find and appraise evidence and provide clear recommendations, whilst others may have a more narrative structure giving an overview of current knowledge on a particular subject. As with other types of study it is important to appraise the evidence for its validity and applicability to your patient, this may be particularly important with guidelines that are written to cover areas where the diseases are endemic and the vector widespread.

The following appraisal checklists may help you with this

The list below provides links to some of the guidelines currently available for vector-borne diseases.

European Scientific Counsel Companion Animal Parasites (ESCCAP)

ESCCAP is an independent, not-for profit organisation consisting of experts in the field of parasitology and public health. Its primary function is to develop free best-practice guidelines for the treatment and control of parasites in pet animals.

The guidelines include descriptions of the biology and transmission of the infectious agents along with useful maps showing their distribution in Europe. This is followed by detailed information on clinical signs and diagnosis as well as approaches to treatment and prevention.

ESCCAP Guideline 5: Control of vector-borne diseases in dogs and cats

ESCCAP (2019) ESCCAP guideline 5: Control of vector-borne diseases in dogs and cats. 3rd ed. [online] Available at: https://www.esccap.org/uploads/docs/znkh6j1d_0775_ESCCAP_Guideline_GL5_v8_1p.pdf [accessed 7 October 2025]

This guideline provides a detailed overview of knowledge of the major vector-borne diseases of dogs and cats including: Leishmaniosis, dirofilariosis, bartonellosis, babesiosis, ehrlichiosis, anaplasmosis and vector-borne viral diseases, alongside mention of a wide range of other vector-borne pathogens.

The authors note that vector-borne pathogens or diseases are important because:

They may be highly pathogenic in dogs and cats.
Their transmission is often unpredictable.
Their diagnosis and control are difficult.
Variable clinical signs can develop after long incubation periods and these are rarely pathognomonic.
Animals may have persistent infections and thus act as reservoirs.
Several are important zoonoses, such as leishmaniosis, borreliosis, rickettsiosis, bartonellosis, anaplasmosis and dirofilariosis.

Leishvet

Leishvet is a scientific association, founded in 2005 by a group of veterinary scientists from academic institutes in the Mediterranean basin and North America, with a primary clinical and scientific interest in leishmaniosis. Its main aim is to improve the knowledge of different aspects of leishmaniosis in veterinary medicine and public health through the development of consensus recommendations based on evidence-based literature and clinical experience.

Practical management of canine and feline leishmaniosis

LeishVet (2018) Canine and feline leishmaniosis: A brief for the practicing veterinarian [online] Available at: https://www.leishvet.org/wp-content/uploads/2018/09/EN-Guidelines.pdf [accessed 3/9/2020]

These provide a succinct summary of the current evidence under the following headings:

Aetiology, distribution and transmission
Clinical manifestations
Diagnosis
Clinical Staging
Therapy
Monitoring
Prevention (including vaccines available for dogs)

Canine leishmaniosis https://www.leishvet.org/fact-sheet/ [accessed 10/9/2020]

Feline leishmaniosis https://www.leishvet.org/fact-sheet-feline-leishmaniosis/ [accessed 10/9/2020]

European Advisory Board on Cat Diseases (ABCD)

The ABCD is a joint initiative of veterinary clinicians, scientists and an industry sponsor set up to communicate scientific developments in feline infectious diseases. They have published guidelines and factsheets (2-page abstracts of the main points contained in the guidelines) on a wide range of infectious diseases affecting cats, divided into viral, bacterial, fungal, protozoan and helminthic disease, alongside more general guidelines on infection control.

The guidelines are available from both the ABCD website as well as in special issues of the Journal of Feline Medicine and Surgery

Dirofilarioses in cats

ABCD (2020) Dirofilarioses in cats [online] Available at: https://www.abcdcatsvets.org/dirofilarioses/ [accessed 3/9/2020]

This guideline includes sections on: agents and lifecycle, epidemiology, pathogenesis and clinical signs, heartworm disease, subcutaneous Dirofilariosis, diagnosis, treatment and follow-up, prevention and One Health.

The guideline makes some comparisons to the condition in dogs, noting that compared to dogs, cats are imperfect hosts to Dirofilaria worms and that after inoculation, only a low number of L3 larvae develop to the adult stage in a small percentage of cats, which can make diagnosis more difficult in cats. The authors also note that the adulticide treatments used in dogs are considered unsafe in cats.

Other sources of information on vector-borne diseases

BSAVA (2016) Scientific information sheets [includes Babesia canis, Leishmaniosis and Lyme disease] Available at: https://www.bsavalibrary.com/content/book/10.22233/9781910443514#chapters [accessed 3/9/2020]
Jacob, S.S. et al (2020) Bovine babesiosis: An insight into the global perspective on the disease distribution by systematic review and meta-analysis. Veterinary Parasitology Volume 283, no. 109136 https://doi.org/10.1016/j.vetpar.2020.109136
Lecollinet, S. et al (2020) Viral equine encephalitis, a growing threat to the horse population in Europe? Viruses, 12 (1), 23 https://doi.org/10.3390/v12010023
Littman M.P. et al (2006) ACVIM small animal consensus statement on Lyme disease in dogs: diagnosis, treatment, and prevention. Journal of Veterinary Internal Medicine, 20 (2) p422-434 https://doi.org/10.1111/j.1939-1676.2006.tb02880.x
Millins, C. et al (2021) Emergence of Lyme Disease on Treeless Islands, Scotland, United Kingdom. Emerging infectious diseases, 27 (2), pp 538–546. https://doi.org/10.3201/eid2702.203862
Neer, T.M. et al (2002) Consensus Statement on Ehrlichial Disease of Small Animals from the Infectious Disease Study Group of the ACVIM*. Journal of Veterinary Internal Medicine, 16 (3) pp. 309-315. https://doi.org/10.1111/j.1939-1676.2002.tb02374.x
RCVS Knowledge In the Spotlight (2018) An overview of Lyme disease in the UK. Available at: https://infocus.rcvsknowledge.org/an-overview-of-lyme-disease-in-the-uk/ [accessed 3/9/2020]
Russo Chagas, U. M. et al. (2021) Correlations between tissue parasite load and common clinical signs in dogs naturally infected by Leishmania infantum, Veterinary Parasitology, 291, no. 109368. https://doi.org/10.1016/j.vetpar.2021.109368

*This position paper which has been approved by the Board of Regents of the American College of Veterinary Internal Medicine has not been peer reviewed.

EFSA vector-borne disease map journals

EFSA’s vector-borne disease map journals: Characterization of 36 vector-borne disease [online] Available at: https://efsa.maps.arcgis.com/apps/PublicGallery/index.html?appid=dfbeac92aea944599ed1eb754aa5e6d1 [Accessed 3/9/2020]

These provide short characterisations of 36 vector-borne diseases, including a summary of the characteristics of the disease agent, transmission, geographical distribution, potential vectors, the impact of the disease on animal health and welfare and a summary of the available prevention and control measures.

About evidence collections

Evidence collections bring together collections of published papers on topics of interest and importance to the veterinary professions. Papers are chosen for relevance and accessibility, with the full text of articles either being available through the RCVS Knowledge library, on open access or from other publications to which a significant number of veterinary professionals are likely to have access. This means that there may be relevant evidence that is not included.

If you would like assistance in searching for further evidence on this topic you may find the following helpful EBVM Toolkit 2: Finding the best available evidence.

If you would like to suggest a paper for inclusion in one of our published evidence collections, or a topic for a future collection, please email library@rcvsknowledge.org